[Characterization of collagen of canine intervertebral disks using the N-methyl-benzothiazol-2-on-hydrazone reaction].

Abstract

Collagen types were studied in the lumbar intervertebral discs of non-chondrodystrophic dogs, 1 to 3 years old. Parts of intervertebral discs were frozen and sections were subjected to the 3-methyl-benzothiazol-2-on-hydrazone (MBTH) method, which permits differentiation of genetic types and maturation stages of collagen. The annulus fibrosus showed a blue (collagen I) and a violet colour (collagen II) at the external zone. The internal zone was more homogeneous and contained a mixture of both colours (collagen I and II). The nucleus pulposus showed only the violet colour, indicative of collagen II. Discs were also dissected at three different zones and submitted to an extraction technique to obtain collagen, then subjected to SDS-polyacrylamide gel electrophoresis and determination of spectrophotometric reactions of MBTH. Both studies demonstrated type I and type II collagens in the external and internal zones of the annulus fibrosus, but only type II in the nucleus pulposus. Collagen characterization, using this technique, would allow for evaluation in pathologic events of the intervertebral discs as well as for establishing the degree of alteration.